Transmitter apparatus, receiver apparatus and radio communication apparatus

ABSTRACT

A MAC unit divides data to be transmitted into number of applying channels, thereby generating transmission data. An applying-channel notifying unit inserts channel information for identifying an applying channel into a used area of the transmission data. Transmission processing units corresponding to the applying channels generate radio frames from the transmission data into which the channel information is inserted, and transmit the generated radio frames to the radio communication apparatus at the reception side.

TECHNICAL FIELD

The present invention relates to a transmitter, a receiver, and a radiocommunication apparatus for transmitting and receiving data using pluralchannels or carriers, and more particularly, to a transmitter, areceiver, and a radio communication apparatus that have a function ofinforming an applying channel that is used to transmit data using thechannels or the carriers.

BACKGROUND ART

In general, data transmission and reception in a communication system iscontrolled in a physical layer (PHY) that is an interface between a datalink layer or a media access control (MAC) and a transmission path, anda data link layer for controlling establishment of a link betweenterminals that carry out communications before starting communicationsor a lower layer of the MAC that carries out access control for a radiomedia.

A radio communication apparatus used in a radio communication systemincludes a PHY unit, a MAC unit, a transmission buffer, and a receptionbuffer. The PHY unit converts control information and user informationof a higher layer into data of a format called a burst, and a basestation and a radio terminal exchange the data in the converted format.

In a radio communication system using anorthogonal-frequency-division-multiplexing (OFDM) modulation system, aPHY unit selects a transmission mode corresponding to a propagationenvironment such as a distance between a base station and a radioterminal and interference conditions, and keeps proper communicationquality based on the prescription of the OFDM.

The MAC unit controls the physical layer by determining a radio terminalthat carries out communications based on the transmission buffer and thereception buffer of a base station and a radio terminal, and atransmission amount. In a radio communication system using a timesharing multiplexing system in which an access point carries out anintegrated control, a MAC unit of the access point determines a methodof using a time domain direction of a carrier based on a predeterminedallocation request amount, thereby managing data transmission andreception between the access point and the radio terminal. A MAC unit ofthe radio terminal transmits and receives data using a slot permitted bythe access point, following the determination of the access point. Thepredetermined allocation request amount is, for example, an allocationrequest amount set in advance, or an allocation request amountcalculated based on a data amount of the transmission buffer addressedto each terminal.

In a radio communication system using a carrier sense multiple access(CSMA), a MAC unit of an access point establishes a synchronization witheach radio terminal using a notification signal and a control signalperiodically transmitted. A MAC unit of a radio terminal executes acarrier sense for a constant time following the notification signal andthe control signal from the access point, confirms that the radioterminal does not compete with other radio terminal, and exchanges datawith the access point.

The transmission buffer and the reception buffer store transmission dataand reception data until the transmission and reception is completed. Inthe case of managing these data for each user connection, thetransmission buffer stores data for each user connection, and notifiesthe MAC unit of the stored amount of data. The transmission buffertransmits the data following the control of transmission. The receptionbuffer confirms received data. When there is a transmission error in thereceived data, the reception buffer requests the access point totransmit the data again.

As explained above, in a radio communication system, a base station oran access point communicates with a radio terminal. Along the recentspread of the Internet, data transmitted between a base station or anaccess point and a radio terminal includes not only e-mails and textdata that do not require a real time processing, but also an increasingamount of moving picture data that require the real time processing,requiring an increase in the communication speed. To meet this request,a radio communication system achieves an increase in the communicationspeed by increasing a transmission capacity using plural channels.

A first conventional technology using plural channels is a personalhandy phone system (PHS) using time division multiple access-timedivision duplex (TDMA-TDD). In the PHS system, a frequency is dividedinto slots on a time domain. Four slots are allocated to a downlink froma base station to a mobile station, and four slots are allocated to anuplink from the mobile station to the base station. One of the slots ofthe uplink and the downlink is used for a control slot, and three slotsare used for communication channels. When starting a communication, themobile station transmits a request for establishing a link channel tothe base station, using the control channel of the uplink. The basestation notifies the mobile station of an applying channel, using thecontrol channel of the downlink. The base station establishes a link inone of the three communication channels. When plural slots are to beused, the mobile station requests the base station to add acommunication channel, using the communication channel in which the linkis established. The base station allocates a slot requested in thecommunication channel addition request, and connects a call to theallocated slot. After the allocated slot is connected, the base stationand the mobile station communicate with each other using plural slots(see, for example, Nonpatent Document 1).

According to a second conventional technology, plural channels aresecured and allocated in advance to a route between a specificcommunication unit system and a specific terminal unit system thatrequire a wide transmission band. With this arrangement, communicationsare executed using plural channels (see, for example, Patent Document1).

According to a third conventional technology, a local station and theother station determine each other in advance two channels that are tobe used in apparatuses of both stations. The apparatuses are set to beable to communicate with each other using these channels. After settingthe channels, the two channels are used as fixed channels (see, forexample, Nonpatent Document 2).

Nonpatent Document 1

ARIB RCR STD-28

Nonpatent Literature 2

IEEE802.11a

Patent Document 1

Japanese Patent Application Laid-open No. 2002-135304

However, according to the first conventional technology, the basestation and the mobile station first communicate with each other usingone channel to determine plural applying channels to determine specificplural applying channels. Therefore, the processing carried out untildata is transmitted using the plural channels becomes complex.

In addition, according to the first conventional technology, the controlinformation is used to determine plural channels to be use. Therefore,data cannot be transferred immediately after communication is started.Consequently, throughput decreases at the start of the communicationuntil the applying channel is determined. Particularly, when high-speedcommunication is to be executed using plural channels, communicationusing the control information carried out until the plural channels aredetermined is not desirable.

Furthermore, according to the first conventional technology, during acommunication using plural channels, it becomes necessary for acommunication terminal to change a channel of a communication terminalto be used for each burst due to a change in the communicationenvironment such as a change in a state of a transmission path andoccurrence of interference during a high-speed movement of thecommunication terminal. In this case, it becomes necessary to notify achange of the applying channel from the transmitter to the receiver.This makes the control more complex, and throughput decreases.

According to the second and the third conventional technologies, pluralapplying channels are fixed. Therefore, when an interference wave entersfrom other system and when a ratio of a desired wave to an interruptionwave becomes small, the number of retransmission increases andthroughput decreases.

The present invention has been achieved in view of the above problems.It is an object of the present invention to provide a transmitter, areceiver, and a communication apparatus capable of communicating witheach other using plural channels, without requiring the transmitter tonotify the receiver of the applying channel in advance.

DISCLOSURE OF INVENTION

The present invention provides a transmitter that is applied to a radiocommunication system and that transmits a radio frame to a receiverusing one or plural channels that can be used. The transmitter includesa transmission MAC unit that divides data into number of applyingchannels, and generates transmission data for each channel using thedivided data, when the data is to be transmitted using two or morechannels a radio-frame generating unit that generates a radio framecontaining each transmission data and a transmission applying-channelnotifying unit that inserts channel information to identify a channelinto each radio frame. The transmitter transmits each radio framecontaining the channel information.

According to the present invention, at the time of transmitting datausing two or more channels, channel information to identify pluralchannels that are used to transmit data is inserted into a radio frameto be transmitted.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic for illustrating a configuration of a radiocommunication system according to a first embodiment of the presentinvention;

FIG. 2 is a schematic for illustrating a configuration of a radiocommunication apparatus shown in FIG. 1;

FIG. 3 is a schematic for illustrating a channel used by the radiocommunication apparatus according to the first embodiment;

FIG. 4 is a schematic for illustrating a format of a radio framegenerated by a radio-frame generating unit shown in FIG. 2;

FIG. 5 is a schematic for illustrating a scrambler of the radio-framegenerating unit shown in FIG. 2;

FIG. 6 is a schematic for illustrating a descrambler of a dataprocessing unit shown in FIG. 2;

FIG. 7 is a flowchart of a processing procedure for a transmissionoperation of the radio communication apparatus according to the firstembodiment;

FIG. 8 is a flowchart of a processing procedure for a receptionoperation of the radio communication apparatus according to the firstembodiment;

FIG. 9 is a schematic for illustrating a configuration of a radiocommunication apparatus according to a second embodiment of the presentinvention;

FIG. 10 is a flowchart of a processing procedure for a transmissionoperation of the radio communication apparatus according to the secondembodiment;

FIG. 11 is a flowchart of a processing procedure for a receptionoperation of the radio communication apparatus according to the secondembodiment;

FIG. 12 is a schematic for illustrating a configuration of a preamble ofa wireless local-area-network (LAN) frame;

FIG. 13 is a schematic for illustrating an example of a special preamblepattern according to a third embodiment of the present invention; and

FIG. 14 is a schematic for illustrating a configuration of the wirelessLAN frame according to the third embodiment.

BEST MODE(S) FOR CARRYING OUT THE INVENTION

Exemplary embodiments of a transmitter, a receiver, and a radiocommunication apparatus according to the present invention will beexplained below in detail with reference to the accompanying drawings.Note that the invention is not limited by the embodiments.

FIRST EMBODIMENT

A radio communication apparatus according to a first embodiment of thepresent invention is explained with reference to FIGS. 1 to 8. FIG. 1 isa schematic for illustrating a configuration of a radio communicationsystem to which the radio communication apparatus according to the firstembodiment is applied. The radio communication system according to thefirst embodiment includes a plurality of radio communication apparatuses1 to 4 (in this example, four apparatuses are used, and the number ofchannels has nothing to do with the number of radio communicationapparatuses) that communicate with each other in a radio transmissionarea 5 using plural channels (in this example, four channels). All theradio communication apparatuses 1 to 4 can communicate with each other,involving no hidden terminal, within the radio transmission area 5,which means that the four radio communication terminals 1 to 4 arelocated within the radio transmission area 5. The radio communicationsystem has a usable frequency band divided into four, including achannel A, a channel B, a channel C, and a channel D, as shown in FIG.2. The radio communication system can communicate using the fourchannels as a maximum. The radio communication apparatuses 1 to 4 cancommunicate in various patterns, such as between one apparatus and oneapparatus, between one apparatus and three apparatuses, and between fourapparatuses and four apparatuses.

Each of the radio communication apparatuses 1 to 4 shown in FIG. 1 hasthe same function. The function of the radio communication apparatus isexplained below with reference to a block diagram of a configuration ofthe radio communication apparatus 1 shown in FIG. 3. The radiocommunication apparatus 1 includes a transmitting unit, a receivingunit, and a common unit 30. The transmitting unit has plural (four, inthis example) transmission processing units 20 a to 20 d correspondingto the number of channels that the local apparatus can use. Thereceiving unit includes reception processing units 50 a to 50 d, andantennas 40 a to 40 d. The antenna 40 a, the transmission processingunit 20 a, and the reception processing unit 50 a correspond to thechannel A. The antenna 40 b, the transmission processing unit 20 b, andthe reception processing unit 50 b correspond to the channel B. Theantenna 40 c, the transmission processing unit 20 c, and the receptionprocessing unit 50 c correspond to the channel C. The antenna 40 d, thetransmission processing unit 20 d, and the reception processing unit 50d correspond to the channel D.

A MAC unit 10 has functions of a transmission MAC unit and a receptionMAC unit in the claims. An applying-channel notifying unit 11 hasfunctions of a transmission applying-channel notifying unit and areception applying-channel notifying unit in the claims.

The transmission processing units 20 a to 20 d and the common unit 30achieve the function of a transmitting unit in the claims. The receptionprocessing units 50 a to 50 d and the common unit 30 achieve thefunction of a receiving unit in the claims. A radio-frame generatingunit 24 and a modulating unit 22 achieve a function of a radio-framegenerating unit in the claims.

The MAC unit 10 has the applying-channel notifying unit 11. When data tobe transmitted is input from the outside, the MAC unit 10 determineschannels that can be used, and allocates the data to be transmitted tothe determined channels. The MAC unit 10 generates transmission data foreach determined channel. The MAC unit 10 determines whether receptiondata input from each of the reception processing units 50 a to 50 dcontains channel information. The MAC unit 10 reassembles a frame of thereception data of each of the channels, containing channel informationaddressed to the local apparatus, selected by the applying-channelnotifying unit 11, and outputs the frame to the controller.

The applying-channel notifying unit 11 inserts channel information intoan unused area of transmission data for each channel generated by theMAC unit 10. The channel information is used to identify an applyingchannel. An identical frame mark or applying-channel-number informationis used for the channel information.

The identical frame mark is a specific pattern of a predetermined numberof bits, and is determined for each of the radio communicationapparatuses 1 to 4 within the radio communication system. Theapplying-channel-number information shows number of applying channelsand positions of the channels. Specifically, channel numbers are set tothe radio communication system in advance. For example, a channel number1 is set to the channel A, a channel number 2 is set to the channel B, achannel number 3 is set to the channel C, and a channel number 4 is setto the channel D. When two channels including the channel A and thechannel B are to be applying channel information of the channel Aincludes “2” as the number of applying channels and “1” as the channelnumber, and channel information of the channel B includes “2” as thenumber of applying channels and “2” as the channel number.Alternatively, all channels are related to bits like “1100”, forexample, to show in which channel transmission data is inserted or whichchannel is used. For example, “1” indicates a channel into whichtransmission data is inserted, and “0” indicates a channel into whichtransmission data is not inserted. When applying-channel-numberinformation is to be inserted into an unused area, communicationapparatus identification information is also inserted into an unusedarea to identify a radio communication apparatus to which data isaddressed out of the radio communication apparatuses 1 to 4 within theradio communication system. For the communication apparatusidentification information, the identical frame mark can be used oridentification information different from the same fame mark can beused.

In the reception processing, when the MAC unit 10 determines thatreception data contains channel information, the applying-channelnotifying unit 11 identifies whether the channel information within thereception data is the identical frame mark addressed to the localapparatus of communication apparatus identification information, andselects reception data addressed to the local apparatus. Theapplying-channel notifying unit 11 outputs the reception data addressedto the local apparatus to the MAC unit 10.

The common unit 30 transmits transmission radio frequency (RF) signalsof the channels output from the transmission processing units 20 a to 20d via the antennas 40 a to 40 d, and outputs reception RF signalsreceived via the antennas 40 a to 40 d to the reception processing units50 a to 50 d of the channels. The common unit 30 can be configured by aswitch, for example.

The transmission processing units 20 a to 20 d have the same function.Each transmission processing unit includes the radio-frame generatingunit 21, the modulating unit 22, and a transmission RF unit 23. Theradio-frame generating unit 21 generates a transmission frame excludinga preamble to establish synchronization within the radio frame shown inFIG. 4. In other words, the radio-frame generating unit 21 generates atransmission frame including a modulation system used in the modulatingunit 22, frame information such as a puncturing rate and a frame length,an encoding-unit initializing section for initializing an encoding unit,an unused area, transmission data, an encoding-unit initializingsection, and dummy data PAD. The radio-frame generating unit 21 encodes,punctures, and interleaves the transmission data input from the MAC unit10, using an encoding system determined in advance for the generatedtransmission frame, an error correction puncturing rule, and aninterleave length. The radio-frame generating unit 21 has a scrambler211 shown in FIG. 5. The radio-frame generating unit 21 inputs apredetermined part of the transmission frame into the scrambler 211 toscramble the transmission frame, and outputs the scrambled transmissionframe to the modulating unit 22.

The modulating unit 22 modulates the transmission frame based on amodulation system determined in advance, generates a radio frame havinga preamble added to the front of the frame information of the modulateddata as shown in FIG. 4, and outputs the generated radio frame to thetransmission RF unit 23. The transmission RF unit 23 converts a baseband frequency of the radio frame into a radio frequency to generate atransmission RF signal, amplifies the generated transmission RF signal,and outputs the amplified transmission RF signal to the common unit 30.

The reception processing units 50 a to 50 d have the same function. Eachreception processing unit has a reception RF unit 51, a demodulatingunit 52, and a data processing unit 53. The reception RF unit 51converts the reception RF signal input from the common unit 30 into abase band signal, and outputs the converted base band signal to thedemodulating unit 52.

The demodulating unit 52 demodulates the base band signal based on ademodulation system determined in advance, and outputs demodulated datato the data processing unit 53. The data processing unit 53 has adescrambler 532 shown in FIG. 6. The data processing unit 53 inputs apredetermined part of the demodulated data into the descrambler 532 todescramble the modulated data, and de-interleaves and decodes the unusedarea between the encoding-unit initializing sections and thetransmission data of the radio frame shown in FIG. 4, based on the frameinformation of the descrambled demodulated data, thereby carrying out aforward error correction (FEC). The data processing unit 53 outputs theforward error-corrected reception data to the MAC unit 10.

The operation of the radio communication system according to the firstembodiment is explained below taking an example of communication carriedout from the radio communication apparatus 1 to the radio communicationapparatus 2 with reference to flowcharts shown in FIGS. 7 and 8.

First, the operation that the radio communication apparatus 1 carriesout to transmit data to the radio communication apparatus 2 is explainedwith reference to the flowchart shown in FIG. 7. When data to betransmitted is input and when this data is to be transmitted usingplural channels, the MAC unit 10 checks usable channels and determinesapplying channels (step S100). Specifically, the MAC unit 10 carries outa reception processing of the channels A to D shown in FIG. 2 using thereception processing units 50 a to 50 d, and executes a carrier sensefor each channel and measures a reception level. When a carrier cannotbe detected or when a reception level is at or below a predeterminedlevel, the MAC unit 10 determines that this channel is not being used,and determines that this channel is to be used.

When the applying channel is determined, the MAC unit 10 divides thetransmission data into the number of applying channels, and generatestransmission data for the applying channels (step S110). For example,when the channel A and the channel C can be used, the MAC unit 10divides the transmission data into two, and generates transmission datafor the channel A and the transmission data for the channel C.

The applying-channel notifying unit 11 inserts channel information intothe unused area of each transmission data generated by the MAC unit 10(step S120). When the identical frame mark is to be used for the channelinformation, the applying-channel notifying unit 11 inserts a specialpattern of the radio communication apparatus 2 into the unused area ofthe channel A and the channel C, respectively. Whenapplying-channel-number information is to be used for the channelinformation, communication apparatus identification information andapplying-channel-number information corresponding to the radiocommunication apparatus 2 are inserted into the unused area of thechannel A and the channel C, respectively. In this case, theapplying-channel-number information to be inserted into the channel A isthe number of applying channels “2” and the channel number “1”, or“1010” by relating each channel to a bit. The applying-channel-numberinformation to be inserted into the channel C is the number of applyingchannels “2” and the channel number “3”, or “1010” by relating eachchannel to a bit.

When the applying-channel notifying unit 11 inserts channel informationinto the unused area, the MAC unit 10 outputs transmission data of eachchannel containing the channel information to the radio-frame generatingunit 21. In this case, the MAC unit 10 outputs the transmission data ofthe channel A to the radio-frame generating unit 21 of the transmissionprocessing unit 20 a, and outputs the transmission data of the channel Cto the radio-frame generating unit 21 of the transmission processingunit 20 c.

The radio-frame generating unit 21 of the transmission processing unit20 a generates a transmission frame (see FIG. 4) using the transmissiondata input from the MAC unit 10, the modulation system used in themodulating unit 22, a puncturing rate, and a frame length. Theradio-frame generating unit 21 encodes, punctures, and interleaves thetransmission data input from the MAC unit 10, using an encoding systemdetermined in advance for the generated transmission frame, an errorcorrection puncturing rule, and an interleave length (step S130). Theradio-frame generating unit 21 inputs a predetermined part of theprocessed transmission frame into the scrambler 211 to scramble thetransmission frame, and outputs the scrambled transmission frame to themodulating unit 22 of the transmission processing unit 20 a.

The modulating unit 22 of the transmission processing unit 20 amodulates the transmission frame based on a modulation system determinedin advance, thereby generating modulated data, adds a preamble to thefront of the frame information of the generated modulated data, andgenerates a radio frame as shown in FIG. 4. The modulating unit 22outputs the generated radio frame to the transmission RF unit 23 (stepS140).

The transmission RF unit 23 converts a base band frequency of the radioframe into a radio frequency to generate a transmission RF signal,amplifies the generated transmission RF signal, and outputs theamplified transmission RF signal to the common unit 30 (step S150).

The radio-frame generating unit 21, the modulating unit 22, and thetransmission RF unit 23 of the transmission processing unit 20 c carryout the operations similar to those of the radio-frame generating unit21, the modulating unit 22, and the transmission RF unit 23 of thetransmission processing unit 20 a, to the transmission data of thechannel C (steps S130 to S150).

The common unit 30 outputs the transmission RF signal input from thetransmission RF unit 23 of the transmission processing unit 20 a to theradio transmission area 5 via the antenna 40 a, and outputs thetransmission RF signal input from the transmission RF unit 23 of thetransmission processing unit 20 c to the radio transmission area 5 viathe antenna 40 c.

The operation that the radio communication apparatus 2 carries out toreceive data transmitted from the radio communication apparatus 1 isexplained next with reference to a flowchart shown in FIG. 8. The commonunit 30 receives RF signals of the channels from the radio transmissionarea 5 using the antennas 40 a to 40 d, and outputs the received RFsignals to the reception processing units 50 a to 50 d.

The reception RF unit 51 of the reception processing unit 50 a convertsthe reception RF signal input from the common unit 30 and received bythe antenna 40 a into a base band signal, and outputs the converted baseband signal to the demodulating unit 52 (step S200).

The demodulating unit 52 of the reception processing unit 50 ademodulates the base band signal based on a demodulation systemdetermined in advance, and outputs the demodulated data to the dataprocessing unit 53 (step S210).

The data processing unit 53 of the reception processing unit 50 a inputsa predetermined part of the demodulated data into the descrambler 532 todescramble the demodulated data. The data processing unit 53de-interleaves and decodes the frame information of the radio frameshown in FIG. 4, and extracts the information of a puncturing rate and aframe length. The data processing unit 53 de-interleaves and decodes theencoding-unit initializing section, the unused area, the transmissiondata (payload), the encoding-unit initializing section, and the PAD,thereby executing a forward error correction (FEC), based on theextracted information (step S220). The data processing unit 53 outputsthe forward error-corrected reception data to the MAC unit 10.

The reception RF unit 51, the demodulating unit 52, and the dataprocessing unit 53 of the reception processing units 50 b to 50 d carryout operations similar to those of the reception RF unit 51, thedemodulating unit 52, and the data processing unit 53 of the receptionprocessing units 50 a, respectively, to the reception RF signals inputfrom the common unit 30 and received by the antennas 40 b to 40 d,respectively (steps S200 to S220).

The MAC unit 10 determines whether each reception data input from thereception processing units 50 a to 50 d contains channel information,and outputs reception data containing the channel information to theapplying-channel notifying unit 11.

The applying-channel notifying unit 11 identifies the channelinformation of the reception data input from the MAC unit 10, andselects reception data addressed to the local apparatus (step S230). Theradio communication apparatus 1 transmits data to the radiocommunication apparatus 2 using the channel A and the channel C asdescribed above. Therefore, the reception data of the receptionprocessing unit 50 a and the reception processing unit 50 c respectivelycontain channel information. When the radio communication apparatus 3transmits data to the radio communication apparatus 4 using the channelB and the channel D, the reception data of the channel B and the channelD also contain channel information. Therefore, four reception datareceived by the reception processing units 50 a to 50 d are input to theapplying-channel notifying unit 11. The applying-channel notifying unit11 identifies whether the channel information of the four reception datashow the local apparatus, and selects reception data addressed to thelocal apparatus. Specifically, when the channel information is theidentical frame mark, the applying-channel notifying unit 11 determineswhether the identical frame mark of each reception data is a specialpattern of the local apparatus. When the channel information containscommunication apparatus identification information, the applying-channelnotifying unit 11 determines whether the communication apparatusidentification information of each reception data is identificationinformation of the local apparatus. Because the radio communicationapparatus 1 transmits data to the radio communication apparatus 2 usingthe channel A and the channel C, the applying-channel notifying unit 11identifies that the channel information contained in the reception datafrom the reception processing unit 50 a and the reception processingunit 50 c are the data addressed to the local apparatus. Theapplying-channel notifying unit 11 notifies the MAC unit 10 that thereception data of the reception processing unit 50 a and the receptionprocessing unit 50 c are the data addressed to the local apparatus.

The MAC unit 10 reassembles the frame data of each reception datanotified from the applying-channel notifying unit 11 (step S240).Specifically, because the radio frame data shown in FIG. 4 is receptiondata, the MAC unit 10 reassembles the frame data by combining thetransmission data within the reception data of each channel togetherinto one transmission data. In other words, the MAC unit 10 combines thetransmission data that are divided and allocated to the channels by theMAC unit 10 of the radio communication apparatus 1 at the transmissionside, into one frame of data. When the channel information is theidentical frame mark or when the applying-channel-number information isrelated to bits, it can be determined in advance that the data aresequentially combined in the order of channel numbers of the applyingchannels. When the number of applying channels and the channel numberare used for the applying-channel-number information, the data can becombined in the order of the channel numbers, thereby obtaining the datain the state of before being divided at the transmission side. The MACunit 10 outputs the reception data of the reassembled frame to theoutside.

As explained above, according to the first embodiment, theapplying-channel notifying unit 11 of the radio communication apparatusat the transmission side inserts the channel information for identifyingplural applying channels for the data transmission into the unused areaof the transmission data generated by the MAC unit 10. Theapplying-channel notifying unit 11 transmits the radio frame containingthe transmission data into which the channel information is inserted.The applying-channel notifying unit 11 of the radio communicationapparatus at the reception side extracts a transmission frame addressedto the local apparatus based on the channel information contained in thetransmission data of the received radio frame. Therefore, the radiocommunication apparatus at the reception side can extract thetransmission frame addressed to the local apparatus and reassemble atransmission frame, without the process of notifying applying channelsfor the data transmission. Even when the radio communication apparatusat the transmission side changes applying channels for the datatransmission at each time of transmitting the radio frame, the radiocommunication apparatus at the reception side can reassemble thereceived frame.

Because the MAC unit 10 of the radio communication apparatus at thetransmission side checks channels of the radio communication system anddetermines the applying channels, it is possible to carry outcommunications using channels of a satisfactory condition of atransmission path. Consequently, throughput can be increased byrestricting the number of times of retransmission.

Because the channel information is inserted into the unused area of thetransmission frame, the processing can be carried out using only the MAClayer.

While the channel information is inserted into the unused area accordingto the first embodiment, the channel information can be also insertedinto the encoding-unit initializing section of the radio frame shown inFIG. 4. In this case, the radio-frame generating unit 21 counts thenumber of bits from the header bit of the frame information of thetransmission frame that is input in the encoding unit (not shown) withinthe radio-frame generating unit 21 that encodes the generatedtransmission frame, and detects data in the encoding-unit initializingsection. When the detected data is an initialization pattern, theradio-frame generating unit 21 initializes the encoding unit using theinitialization pattern of the encoding-unit initializing section. Whenthe detected data is not the initialization pattern, that is, whenchannel information is inserted in the encoding-unit initializingsection, the radio-frame generating unit 21 counts the number of bits inthe encoding-unit initializing section, and detects the end of theencoding-unit initializing section. The radio-frame generating unit 21resets the encoding unit at the end of the encoding-unit initializingsection, and encodes the unused area and the transmission data of thetransmission frame (see FIG. 4).

The frame information contains the information of the modulation systemused in the modulating unit 22, the puncturing rate, and the framelength. The radio-frame generating unit 21 calculates a length of theunused area and the transmission data based on the frame lengthcontained in the frame information. The radio-frame generating unit 21counts the number of bits calculated from the start of the unused area,thereby detecting an end bit of the encoding-unit initializing sectionafter the transmission data. The radio-frame generating unit 21 resetsthe encoding unit at the end of the encoding-unit initializing section.

As explained above, when the radio-frame generating unit 21 detects theencoding-unit initializing section and resets the encoding unit, channelinformation can be inserted into the encoding-unit initializing section.Only the data to be transmitted can be inserted into the transmissiondata, and the channel information can be notified without decreasing thetransmission capacity and without expanding the radio frame.

SECOND EMBODIMENT

A radio communication apparatus according to a second embodiment of thepresent invention is explained with reference to FIGS. 9 to 11. Theradio communication apparatus according to the second embodiment issimilar to the radio communication apparatus according to the firstembodiment shown in FIG. 1, and therefore, their redundant explanationis omitted.

FIG. 9 is a schematic for illustrating a configuration of the radiocommunication apparatus 1 according to the second embodiment. The radiocommunication apparatus 1 shown in FIG. 3 is different from the radiocommunication apparatus 1 shown in FIG. 2 according to the firstembodiment as follows. A radio-frame generating unit 24 is provided inplace of the radio-frame generating unit 21 within the transmissionprocessing units 20 a to 20 d. A data processing unit 54 is provided inplace of the data processing unit 53 within the reception processingunits 50 a to 50 d. An applying-channel notifying unit 60 is used inplace of the applying-channel notifying unit 11 within the MAC unit 10.Constituent parts that have functions similar to those of the firstembodiment are assigned with like reference numerals, and theirredundant explanation is omitted.

The applying-channel notifying unit 60 has functions of the transmissionapplying-channel notifying unit and the reception applying-channelnotifying unit in the claims.

The applying-channel notifying unit 60 determines whether to execute anyone or both of a special preamble processing and a special scrambling tothe transmission data of an applying channel determined by the MAC unit10. When the special preamble processing is to be executed, theapplying-channel notifying unit 60 outputs a special preamble patterndetermined in advance in the radio communication apparatus at the datatransmission side to the modulating unit 22 of the applying channel.When the special scramble processing is to be executed, theapplying-channel notifying unit 60 outputs channel information to theradio-frame generating unit 24 of the applying channel, as an initialvalue of scrambling.

The applying-channel notifying unit 60 outputs to the MAC unit 10 anotification about whether a preamble pattern is a special preamblepattern input from the demodulating unit 52 of the reception processingunits 50 a to 50 d, or channel information having the equivalent initialvalue obtained by the descramble processing input from the dataprocessing unit 54.

The radio-frame generating unit 24, in addition to achieving thefunction of the radio-frame generating unit 21 according to the firstembodiment, carries out a scramble processing using channel informationfor the initial value and using a predetermined part of the radio frameas input data, when the channel information is input as the initialvalue of scrambling.

When a special preamble pattern is input, the modulating unit 22 insertsthe input special preamble pattern into the preamble shown in FIG. 4.

The demodulating unit 52 determines whether the preamble within theradio frame is a special preamble pattern. When the preamble within theradio frame is a special preamble pattern, the demodulating unit 52notifies the applying-channel notifying unit 60 to this effect.

The data processing unit 54, in addition to achieving the function ofthe data processing unit 53 according to the first embodiment, outputsan initial value output by the descramble processing on theapplying-channel notifying unit 60 when the demodulated data isdescrambled using a predetermined part as input data.

The operation of the radio communication system according to the secondembodiment is explained below taking an example of communication carriedout from the radio communication apparatus 1 to the radio communicationapparatus 2 with reference to flowcharts shown in FIG. 10 and FIG. 11.The operations at steps S300 and S310 where the MAC unit 10 checksusable channels and generates a transmission frame corresponding to thedetermined applying channel are the same as the operations according tothe first embodiment, and therefore, their detailed explanation isomitted.

First, the operation that the radio communication apparatus 1 carriesout to transmit data to the radio communication apparatus 2 is explainedwith reference to the flowchart shown in FIG. 10. When data to betransmitted is input and when this data is to be transmitted usingplural channels, the MAC unit 10 checks usable channels and determinesapplying channels, and generates transmission data corresponding to thedetermined applying channels (steps S300 and S310). The MAC unit 10notifies the applying-channel notifying unit 60 of the applyingchannels. In this example, the MAC unit 10 determines that the channel Aand the channel C are to be used, and notifies the applying-channelnotifying unit 60 of these two channels.

The applying-channel notifying unit 60 determines whether a specialpreamble processing is to be executed to transmission frames of thechannels notified from the MAC unit 10 (step S320). When a specialpreamble processing is to be executed, the applying-channel notifyingunit 60 outputs a special preamble pattern corresponding to thedata-transmitting radio communication apparatus, to the modulating unit22 of the applying channels (step S330). Because the channel A and thechannel C are used, the applying-channel notifying unit 60 outputs aspecial preamble pattern corresponding to the radio communicationapparatus to the modulating unit 22 of the transmission processing unit20 a and the transmission processing unit 20 c, respectively.

The applying-channel notifying unit 60 determines whether a specialscramble processing is to be executed to transmission frames of thechannels notified from the MAC unit 10 (step S340). When a specialscramble processing is to be executed, the applying-channel notifyingunit 60 outputs channel information to the radio-frame generating unit24 of the applying channels, as an initial value of scrambling (stepS350). Because the channel A and the channel C are used, theapplying-channel notifying unit 60 outputs the channel information tothe radio-frame generating unit 24 of the transmission processing unit20 a and the transmission processing unit 20 c, respectively, to theradio communication apparatus 2.

The radio-frame generating unit 24 of the transmission processing unit20 a generates a transmission frame (see FIG. 4) using the transmissiondata input from the MAC unit 10. The radio-frame generating unit 24encodes, punctures, and interleaves the transmission data input from theMAC unit 10, using an encoding system determined in advance for thegenerated transmission frame, an error correction puncturing rule, andan interleave length. When channel information is input as an initialvalue of scrambling, the radio-frame generating unit 24 inputs apredetermined part of the transmission frame into the scrambler 211using the input channel information, and scrambles the transmissionframe (step S360). The radio-frame generating unit 24 outputs thescrambled transmission frame to the modulating unit 22 of thetransmission processing unit 20 a.

The modulating unit 22 of the transmission processing unit 20 amodulates the transmission frame based on a modulation system determinedin advance, thereby generating the radio frame shown in FIG. 4. Themodulating unit 22 outputs the generated radio frame to the transmissionRF unit 23 (step S370). In this case, when a special preamble pattern isinput, the modulating unit 22 inserts the special preamble pattern intothe preamble of the radio frame shown in FIG. 4.

The transmission RF unit 23 converts a base band frequency of the radioframe into a radio frequency to generate a transmission RF signal,amplifies the generated transmission RF signal, and outputs theamplified transmission RF signal to the common unit 30 (step S380).

The radio-frame generating unit 24, the modulating unit 22, and thetransmission RF unit 23 of the transmission processing unit 20 c carryout the operations similar to those of the radio-frame generating unit24, the modulating unit 22, and the transmission RF unit 23 of thetransmission processing unit 20 a to the transmission data of thechannel C (steps S360 to S380).

The common unit 30 outputs the transmission RF signal input from thetransmission RF unit 23 of the transmission processing unit 20 a to theradio transmission area 5 via the antenna 40 a, and outputs thetransmission RF signal input from the transmission RF unit 23 of thetransmission processing unit 20 c to the radio transmission area 5 viathe antenna 40 c.

The operation that the radio communication apparatus 2 carries out toreceive data transmitted from the radio communication apparatus 1 isexplained next with reference to a flowchart shown in FIG. 11. Thecommon unit 30 receives RF signals of the channels from the radiotransmission area 5 using the antennas 40 a to 40 d, and outputs thereceived RF signals to the reception processing units 50 a to 50 d.

The reception RF unit 51 of the reception processing unit 50 a convertsthe reception RF signal input from the common unit 30 and received bythe antenna 40 a into a base band signal, and outputs the converted baseband signal to the demodulating unit 52 (step S400).

The demodulating unit 52 of the reception processing unit 50 ademodulates the base band signal based on a demodulation systemdetermined in advance, and outputs the demodulated data to the dataprocessing unit 53 (step S410) In this case, the demodulating unit 52determines whether a preamble within the radio frame is a specialpreamble pattern (step S420). When the preamble within the radio frameis a special preamble pattern, the demodulating unit 52 notifies theapplying-channel notifying unit 60 that the preamble within the radioframe is a special preamble pattern.

The data processing unit 54 of the reception processing unit 50 ade-interleaves and decodes the unused area between the encoding-unitinitializing sections and transmission data of the radio frame shown inFIG. 4, thereby executing a forward error correction (FEC), andgenerates reception data, based on the frame information of thedemodulated data. The data processing unit 54 of the receptionprocessing unit 50 a inputs a predetermined part of the demodulated datainto the descrambler 532, thereby descrambling the demodulated data, andobtains an initial value (step S430). The data processing unit 54determines whether the obtained initial value contains channelinformation (step S440). When the obtained initial value containschannel information, the data processing unit 54 outputs the obtainedinitial value to the applying-channel notifying unit 60.

The reception RF unit 51, the demodulating unit 52, and the dataprocessing unit 54 of the reception processing units 50 b to 50 d carryout operations similar to those of the reception RF unit 51, thedemodulating unit 52, and the data processing unit 54 of the receptionprocessing units 50 a, respectively, to the reception RF signals inputfrom the common unit 30 and received by the antennas 40 b to 40 d,respectively (steps S400 to S440).

The applying-channel notifying unit 60 extracts reception data having anotification input from the demodulating unit 52 of the receptionprocessing units 50 a to 50 d that a preamble pattern is a specialpreamble pattern, or reception data of a channel having the equivalentinitial value obtained by the descramble processing input from the dataprocessing unit 54 (step S450). As described above, the radiocommunication apparatus 1 transmits data to the radio communicationapparatus 2 using the channel A and the channel C. Therefore, theapplying-channel notifying unit 60 receives the information that thepreamble of the radio frame is a special preamble pattern from thedemodulating unit 52 of the reception processing unit 50 a and thereception processing unit 50 c, respectively, or an initial value ofscrambling from the data processing unit 54. When the radiocommunication apparatus 3 and the radio communication apparatus 4 arecommunicating with each other using the channel B and the channel D, theapplying-channel notifying unit 60 receives the information that thepreamble of the radio frame is a special preamble pattern from thedemodulating unit 52 of the reception processing unit 50 b and thereception processing unit 50 d, respectively, or an initial value ofscrambling from the data processing unit 54. The applying-channelnotifying unit 60 determines whether the notified special preamblepattern or the channel information notified as an initial value isaddressed to the local apparatus, and notifies the MAC unit 10 of thespecial preamble pattern or the channel information addressed to thelocal apparatus.

The MAC unit 10 reassembles the frame data of each reception data usingthe channel information input from the applying-channel notifying unit60 (step S460). In this case, the frames of the reception data of thechannel A and the channel C are reassembled. Specifically, because theradio frame data shown in FIG. 4 is reception data, the MAC unit 10reassembles the frame data by combining the transmission data within thereception data of each channel together into one transmission data. Inother words, the MAC unit 10 combines the transmission data that aredivided and allocated to the channels by the MAC unit 10 of the radiocommunication apparatus 1 at the transmission side, into one frame ofdata. The MAC unit 10 outputs the reception data of the reassembledframe to the controller.

As explained above, according to the second embodiment, theapplying-channel notifying unit 60 of the radio communication apparatusat the transmission side inserts the channel information for identifyingplural applying channels for the data transmission as the preamble ofthe radio frame or as an initial value of the scramble processing. Theapplying-channel notifying unit 60 transmits the radio frame containingthis channel information. The applying-channel notifying unit 60 of theradio communication apparatus at the reception side extracts receptiondata of a channel containing a transmission frame addressed to the localapparatus, based on the channel information contained in the initialvalue extracted by the descrambling of the demodulated data. Therefore,the radio communication apparatus at the reception side can extract thetransmission frame addressed to the local apparatus and reassemble atransmission frame, without the process of notifying applying channelsfor the data transmission. Even when the radio communication apparatusat the transmission side changes applying channels for the datatransmission at each time of transmitting the radio frame, the radiocommunication apparatus at the reception side can reassemble thereceived frame.

Because the channel information is inserted as the preamble of the radioframe or the initial value of the scramble processing, the processingcan be carried out using only the physical layer. At the same time, thechannel information can be notified without expanding the radio frame.

According to the second embodiment, the demodulating unit 52 determineswhether the preamble pattern is a special preamble pattern, and the dataprocessing unit 54 has the descrambler 532 and descrambles thedemodulated data. Alternatively, the demodulating unit 52 can have thedescrambler 532 and output the descrambled data to the data processingunit 54, and the data processing unit 54 can determine whether thepreamble pattern is a special preamble pattern.

Furthermore, according to the second embodiment, the demodulating unit52 determines whether a preamble pattern is a special preamble pattern,and the descrambler 532 of the data processing unit 54 descrambles thedemodulated data, thereby extracting channel information contained inthe initial value. Alternatively, any one or both of the determining ofthe special preamble pattern and the descramble processing can beexecuted.

THIRD EMBODIMENT

A preamble pattern according to a third embodiment of the presentinvention is explained with reference to FIGS. 12 to 14. According tothe second embodiment, a special preamble pattern is used for thepreamble of the radio frame, thereby identifying a applying channel.According to the third embodiment, a special preamble pattern when awireless local-area-network (LAN) is used for the radio communicationsystem is explained.

FIG. 12 is a schematic for illustrating a configuration of a preamble ofa wireless LAN frame prescribed by the IEEE802.11a. The preamble of thewireless LAN frame includes a short preamble having ten short trainingsymbols S, and a long preamble having a guard interval GI and two longtraining symbols L. The short training symbol S is a signal having 16sample sections. The long training symbol L is a signal having 64 samplesections.

In the wireless LAN, it is known in advance that the preamble includesten short training symbols S, a guard interval GI, and two long trainingsymbols L in this order. Therefore, a reception side executes asynchronization processing and a frequency deviation subtractionprocessing that are necessary for a reception processing, by carryingout a correlation processing of the preamble positioned at the head ofthe received signal.

When the radio communication apparatus 1 according to the secondembodiment is used for the wireless LAN, a pattern having reversedpolarities of the short training symbols S and the long training symbolsL of the preamble shown in FIG. 12 is used as a special preamblepattern. For example, a pattern having symbols as shown in FIG. 13 isused as a special preamble pattern, which includes two short trainingsymbols S, two short training symbols RS having reversed polarities, twoshort training symbols S, two short training symbols RS having reversedpolarities, two short training symbols S, a guard interval GI, a longtraining preamble L, and a long training symbol RL having a reversedpolarity.

Because the preamble of the wireless LAN includes ten short trainingsymbols S and two long training symbols L, there are various patterns inwhich polarities are reversed. It is sufficiently possible to allocateindividual special preamble patterns to a plurality of the radiocommunication apparatuses 1 within the wireless LAN.

The demodulating unit 52 is set in advance with information that a partof polarities of the preamble are reversed. Correlations of preamblesduring the synchronization processing are different between the preambleshown in FIG. 12 and the preamble using the special preamble patternshown in FIG. 13. Based on the difference of correlations, thedemodulating unit 52 determines whether the preamble pattern is aspecial preamble pattern. When the preamble pattern is a specialpreamble pattern, the demodulating unit 52 notifies the applying-channelnotifying unit 60 that the preamble pattern is a special preamblepattern.

Based on the notification from the demodulating unit 52 of the receptionprocessing units 50 a to 50 d that the preamble pattern is a specialpreamble pattern, the applying-channel notifying unit 60 determineswhether the special preamble pattern indicates the local apparatus, andnotifies the MAC unit 10 about a result of the determination made.

When the MAC unit 10 is notified from the applying-channel notifyingunit 60 that the input special preamble pattern indicates the localapparatus, the MAC unit 10 reassembles the frame of the reception dataof the channel, and outputs the reception data of the reassembled frameto the controller.

As explained above, according to the third embodiment, when data is tobe transmitted using plural channels, a special preamble pattern havinga part of polarities of the preamble of the wireless LAN reversed isused as a preamble of the wireless LAN frame. Therefore, in the wirelessLAN system, it is possible determine whether a normal channel is beingused or plural channels are being used, by determining a preamble. Theradio communication apparatus at the reception side can extract atransmission frame addressed to the local apparatus and cam reassemble atransmission frame, without using the process of notifying a applyingchannel for the data transmission. Even when the radio communicationapparatus at the transmission side changes applying channels for thedata transmission at each time of transmitting the radio frame, theradio communication apparatus at the reception side can reassemble thereceived frame.

In determining whether a special preamble pattern indicates the localapparatus, when the preamble pattern of the wireless LAN frame is aspecial preamble pattern that does not indicate the local apparatus, theapplying-channel notifying unit 60 can stop the reception processing ofthe wireless LAN frame after the preamble. With this arrangement, powerconsumption during the reception processing of the radio communicationapparatus can be restricted, and consumption of the batteries can berestricted.

According to the third embodiment, a special pattern is set in thepreamble of the wireless LAN frame to notify an applying channel.Alternatively, a plural-channel use notification section for settingchannel information can be inserted into between the preamble and theheader information of the wireless LAN frame, as shown in FIG. 14. Aspecial preamble pattern can be inserted into the plural-channel usenotification section, or plural-channel use notification data for onedata time of orthogonal frequency division multiplexing (OFDM) differentfrom the special preamble pattern can be inserted into theplural-channel use notification section.

While a channel according to a frequency is explained according to thefirst and the second embodiments, the channel is not limited to thechannel according to the frequency. For example, a channel can be basedon time, a symbol, and space, that is, multi input and multi output(MIMO).

According to the first and the second embodiments, it is explained thatthe antenna 40 a to the antenna 40 d correspond to the transmissionreceiving units 20 a to 20 d and the reception processing units 50 a to50 d at a rate of one to one. This correspondence is not limited to thisrate. For example, one or plural antennas can be used. In other words,one antenna can correspond to plural channels.

According to the first and the second embodiments, while thetransmission RF unit 23 and the reception RF unit 51 are prepared foreach channel, the relation is not limited to this. For example, a singleunit of the transmission RF unit 23 can simultaneously process data offour channels. Alternatively, a single unit of the reception RF unit 51can simultaneously process data of four channels.

INDUSTRIAL APPLICABILITY

As explained above, the radio communication apparatus according to thepresent invention is effectively used for a radio communication systemthat transmits data using plural channels or plural carriers.Particularly, the radio communication apparatus according to the presentinvention is suitable for a radio communication system in which pluralchannels or plural carriers to be used need to be notified to the datareception side.

1. A transmitter that is applied to a radio communication system, andtransmits a radio frame to a receiver using at least one availablechannel, the transmitter comprising: a transmission media-access-controlunit that divides, when the transmitter transmits data using two or morechannels, the data into number of applying channels to be used, andgenerates transmission data for each of the channels using divided data;a radio-frame generating unit that generates a radio frame that containseach of the transmission data; and a transmission applying-channelnotifying unit that inserts channel information for identifying achannel into each radio frame, wherein the transmitter transmits eachradio frame containing the channel information.
 2. The transmitteraccording to claim 1, wherein the transmission applying-channelnotifying unit inserts the channel information into an unused area oftransmission data generated by the transmission media-access-controlunit.
 3. The transmitter according to claim 1, wherein the transmissionapplying-channel notifying unit inserts the channel information into apreamble of the radio frame.
 4. The transmitter according to claim 1,wherein the transmission applying-channel notifying unit notifies thechannel information to the radio-frame generating unit, when theradio-frame generating unit generates the radio frame using the channelinformation, and the radio-frame generating unit executes apredetermined transmission processing on each transmission data, anduses the channel information for an initial value of a scrambleprocessing as one of the transmission processing, when generating theradio frame.
 5. The transmitter according to claim 1, wherein theradio-frame generating unit includes an encoding unit that encodes thetransmission data contained in the radio frame, the transmissionapplying-channel notifying unit inserts the channel information into anencoding-unit initializing section for initializing the encoding unitwithin the radio frame, and the radio-frame generating unit initializesthe encoding unit at a timing when an input of a pattern of theencoding-unit initializing section to the encoding unit is completed. 6.The transmitter according to claim 1, wherein the transmissionmedia-access-control unit checks a reception state of a plurality ofchannels belonging to the radio communication system, and determines theapplying channel based on a result of the check.
 7. The transmitteraccording to claim 1, wherein the channel information includes at leastone of an identical frame mark for identifying whether a radio framereceived by the receiver is addressed to a local apparatus andapplying-channel-number information indicating a channel number of theapplying channel.
 8. The transmitter according to claim 7, wherein theapplying-channel-number information includes information indicating anorder of transmission frames generated by the transmissionmedia-access-control unit by dividing transmission data.
 9. Thetransmitter according to claim 3, wherein when a wirelesslocal-area-network is used as the radio communication system, thechannel information to be inserted into the preamble is a specialpreamble pattern obtained by inverting a polarity of a part of eitherone of a short training symbol and a long training symbol thatconstitute a preamble of the wireless local-area-network frame.
 10. Areceiver that is applied to a radio communication system, and receives aradio frame from a transmitter in the radio communication system usingat least one available channel, the receiver comprising: a receivingunit that generates reception data by performing a predeterminedreception processing on the radio frame received from the channels; areception applying-channel notifying unit that extracts reception dataaddressed to a local apparatus based on either one of informationextracted by the reception processing and channel information containedin the reception data; and a reception media-access-control unit thatgenerates a reception frame by reassembling an original transmissionframe from the reception data extracted by the receptionapplying-channel notifying unit.
 11. The receiver according to claim 10,wherein the receiving unit executes a descramble processing as thepredetermined reception processing, and outputs an initial valueextracted by the descramble processing to the reception applying-channelnotifying unit.
 12. The receiver according to claim 10, wherein thereceiving unit executes a demodulation processing as the predeterminedreception processing, and outputs at least one of a preamble generatedby the demodulation processing and data of an encoding-unit initializingsection contained in demodulated data to the reception applying-channelnotifying unit.
 13. A radio communication apparatus that is applied to aradio communication system, and communicates with other radiocommunication apparatus in the radio communication system using at leastone available channel, the radio communication apparatus comprising: atransmitter that includes a transmission media-access-control unit thatdivides, when the transmitter transmits data using two or more channels,the data into number of applying channels to be used, and generatestransmission data for each of the channels using divided data; aradio-frame generating unit that generates a radio frame that containseach of the transmission data; and a transmission applying-channelnotifying unit that inserts channel information for identifying achannel into each radio frame, wherein the transmitter transmits eachradio frame containing the channel information; and a receiver thatincludes a receiving unit that generates reception data by performing apredetermined reception processing on the radio frame received from thechannels; a reception applying-channel notifying unit that extractsreception data addressed to a local apparatus based on either one ofinformation extracted by the reception processing and channelinformation contained in the reception data; and a receptionmedia-access-control unit that generates a reception frame byreassembling an original transmission frame from the reception dataextracted by the reception applying-channel notifying unit.
 14. Theradio communication apparatus according to claim 13, wherein thetransmission applying-channel notifying unit inserts the channelinformation into an unused area of transmission data generated by thetransmission media-access-control unit, and the receptionapplying-channel notifying unit extracts the channel information fromthe reception data.
 15. The radio communication apparatus according toclaim 13, wherein the transmission applying-channel notifying unitnotifies the channel information to the radio-frame generating unit,when the radio-frame generating unit generates the radio frame using thechannel information, the radio-frame generating unit executes apredetermined transmission processing on each transmission data, anduses the channel information for an initial value of a scrambleprocessing as one of the transmission processing, when generating theradio frame, and the receiving unit executes a descramble processing asthe predetermined reception processing, and outputs an initial valueextracted by the descramble processing to the reception applying-channelnotifying unit.
 16. The radio communication apparatus according to claim13, wherein the transmission applying-channel notifying unit inserts thechannel information into a preamble of the radio frame, and thereceiving unit executes a demodulation processing as the predeterminedreception processing, and outputs a preamble generated by thedemodulation processing to the reception applying-channel notifyingunit.
 17. The radio communication apparatus according to claim 13,wherein the radio-frame generating unit includes an encoding unit thatencodes the transmission data contained in the radio frame, thetransmission applying-channel notifying unit inserts the channelinformation into an encoding-unit initializing section for initializingthe encoding unit within the radio frame, the radio-frame generatingunit initializes the encoding unit at a timing when an input of apattern of the encoding-unit initializing section to the encoding unitis completed, and the receiving unit executes a demodulation processingas the predetermined reception processing, and outputs data of anencoding-unit initializing section contained in demodulated data to thereception applying-channel notifying unit.
 18. The radio communicationapparatus according to claim 13, wherein the transmissionmedia-access-control unit checks a reception state of a plurality ofchannels belonging to the radio communication system has, and determinesthe applying channel based on a result of the check.
 19. The radiocommunication apparatus according to claim 13, wherein the channelinformation includes at least one of an identical frame mark foridentifying whether a radio frame received by the receiver is addressedto a local apparatus and applying-channel-number information indicatinga channel number of the applying channel.
 20. The radio communicationapparatus according to claim 19, wherein the applying-channel-numberinformation includes information indicating an order of transmissionframes generated by the transmission media-access-control unit bydividing transmission data.
 21. The radio communication apparatusaccording to claim 16, wherein when a wireless local-area-network isused as the radio communication system, the channel information to beinserted into the preamble is a special preamble pattern obtained byinverting a polarity of a part of either one of a short training symboland a long training symbol that constitute a preamble of the wirelesslocal-area-network frame.